Well, yeah they are her kids. We know that now. The discussion began before the Young Avengers even started.

I wonder who the lost souls Wanda snatched belonged to.

oops. sry i tend to read the begining and forget that other people have talked after...oh well
with Stature on the Pro side, i wonder if she will still be part of Young Avengers

Well, if you go by how she originally concieved them, then they were parts of Mephisto that had went missing, in part, because of Franklin "I can create my own universe" Richards. He set it up, using Master Panademonium's accident to set things up so Master P could retrieve the 5 parts for Mephisto, tho Master P thought it was for his own soul.
So, the kids belong to Mephisto or something. Depends on how you look at it and who will retcon what.